Foam weatherseals (weather stripping) are well known in the art as a way of preventing water, air and/or other unwanted contaminants from seeping past a closed door, window, or the like. More specifically, a weatherseal is generally applied to a door jamb or window frame for contact with the respective door or window when closed. A typical weatherseal can have a complex geometric profile and is typically manufactured in continuous or cut lengths to provide a seal between the door or window and associated jamb. Conventional weatherseals typically consist of a foam profile attached to a rubber or plastic extrusion and are usually attached to a door or window frame by inserting a portion of the extrusion into a door or window kerf. Alternatively, the weatherseal may be attached to a door jamb, window frame or other component using adhesive tape, fasteners, or the like.
Conventional weatherseals, while being effective at preventing the passage of water and other contaminants, are generally not effective at slowing spread of a fire and/or smoke around the closed door or window.
Intumescent materials are known to help retard the spread of fires. Specifically, intumescent materials swell when exposed to the elevated temperatures caused by a fire. When swollen, the materials are poor conductors of heat, and thus slow the spread of the fire. Intumescents may also include hydrates, that release water vapor at elevated temperatures, to also slow the spread of the fire.
Some known applications incorporate intumescent materials and weatherseals. For example, U.S. Pat. No. 4,676,025 shows a remotely activatable seal that incorporates an intumescent bead of material that is activated by a heat source (i.e., coiled high resistance wire) disposed in the intumescent material. However, there are a variety of potential problems for such a seal, since the high resistance wire must be activated by some alarm condition, requiring a control system, as well as a reliable power source. It is contemplated that the electrical current and power required to activate initially and fully the intumescent material may not be available in an emergency. Moreover, there may be a reliability concern. Repeated opening and closing of the door, window, etc. being sealed and resultant flexing of the embedded high resistance wire and associated external wiring may compromise the wiring or cause an open circuit condition, making the remote, early activation of the intumescent portion of the seal ineffective. The intumescent bead is also encased fully within the resilient cellular foam core. Accordingly, when installed in a door frame or other opening, the intumescent bead of the weatherseal does not have direct contact against the door jamb or frame. Accordingly, when activated, the intumescent material could expand unevenly, in a relatively uncontrolled manner, creating gaps around the door slab. Flame and smoke could breach the door slab and frame, rendering the seal unsatisfactory for its intended purpose.
Moreover, this prior art seal would be relatively expensive to manufacture and install, since it requires the inclusion of the high resistance wire coil within the seals and interconnecting the coils with external wiring and a control/power supply external to the seals.
There is a need in the art for an easily and inexpensively manufactured weatherseal that is capable of sealing a door, window, or the like during normal, i.e., non-fire, operating conditions, but that also retards the spread of a fire beyond the closure. Further, there is a need in the art to be able to install such weatherseals in a manner consistent with non-intumescent seals, without the need to electrically interconnect the seals to each other or to an external control/power supply.